Market If Touched - MIT
  
A market if touched (MIT) order is something you give to your broker if you want to buy (or sell) stocks or securities at a certain price. If the price reaches (or touches) a specific number, the broker can go ahead and buy (or sell) at that market price.
It's kind of like a limit order, but if you have, say, 100,000 shares of whatever.com and your MIT number is $22.00 and the stock traded lots of shares in the mid-$21 range...but then spiked, and 1,000 shares traded at $22.00...then that's not enough value to clear you out of the 100,000 shares you wanted to sell. So that 1,000 share volume is kind of a goosing to the broker to then go out and "market," or make a few phone calls into the brokerage that sponsored whoever was buying at $22.00.
Kinda like the virtual brokerage version of, "Yeah, go get me some more o' dat."